Can I make this system work? (undervolting help please)

[Kuli24]

I have an evga x58 sli3 mobo,
i7 930 cpu with H80i cooler,
7970 crossfired with a 280x,
8gb ram (2x4gb),
NO dvd drives or card readers
Antec Truepower 650w psu

I want to make this system work while I try to build up money for a psu.
It currently runs games, but sometimes randomly slows down and the audio volume goes up and down drastically. Can I get away with undervolting my cpu and gpu's so my psu works well for the time being? My gpu's are at 1050mv by default which seems low already and my cpu is at 1.1825v. Advice?
Thanks.

 

[beers]

Take out one of the GPUs, 650w is insufficient for that setup at load.

 

[Kuli24]

Take out one of the GPUs, 650w is insufficient for that setup at load.

for now i'd be fine running them at say 800mhz each instead of stock 1000mhz if it means it takes less wattage. Or am I severely over the limit?

 

[Kuli24]

Update: I have a lead on a guy selling an OCZ ZT 750w for $40US. I think I'll snatch it up. Think it'll handle this situation well?

 

[H4rdR3s37]

Update: I have a lead on a guy selling an OCZ ZT 750w for $40US. I think I'll snatch it up. Think it'll handle this situation well?

Probably yes. Underclocking may help also.